Sources: NFL eyes start of HGH testing

The NFL is expected to have HGH testing within five to 10 days on a marginal level, according to sources from both the league and its players union, though there has been no agreement reached yet between the two sides.

The NFL and NFLPA have received pressure from politicians, the latest being Sen. John McCain, who has joined those urging the league and union to commence testing.

The union has balked at an aggressive program that would include game-day testing because it claims that agencies such as the World Anti-Doping Agency have not provided ample information to specific questions the NFLPA has on the scientific evidence it wants before moving forward with a full testing program.

Among the requests that have not been satisfied, according to union sources, is population studies that provide data on the normal ranges of human growth hormone naturally produced by the body.

The NFL has maintained that scientists believe the testing procedures are reliable. If there is HGH testing agreed upon during the next 10 days, the union wants it done on a marginal level, sources said. But NFL spokesman Greg Aiello said the league did not know what "marginal testing" means.

Chris Mortensen is a senior NFL analyst for ESPN.